


Weekly Private Sessions

by KwIl



Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Blow Jobs, Creampie, Cum Swallowing, Cunnilingus, Dom/sub Play, Erotica, Established Relationship, F/M, Face-Fucking, Hand Jobs, Orgasm Delay/Denial, Pain Kink, Rough Sex, Scars, Secret Relationship, Size Difference, Smut, Teacher-Student Relationship, Vaginal Sex
Language: English
Status: Completed
Published: 2020-07-24
Updated: 2020-07-24
Packaged: 2021-03-05 02:14:21
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 8,581
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25476712
Author URL: https://archiveofourown.org/users/KwIl/pseuds/KwIl
Summary: Lysithea asks her professor for some additional private help with her studies.Months later, she's still visiting her professor, but for completely different reasons.
Relationships: My Unit | Byleth/Lysithea von Ordelia
Kudos: 57





	Weekly Private Sessions

Byleth was surprised he was able to hear such a quiet knock on his door, but he figured knowing it was inevitably coming made it easier to notice. He was pretty used to her showing up at this time every week.

"Professor…?" Byleth heard an equally soft voice call out to him. It was approaching the late evening and most students had retreated to their dormitories for the night. That meant it was the earliest someone could visit him without anyone else noticing.

The professor of the Golden Deer class opened his door. Upon doing so, a girl half his size quickly leapt into his room. Byleth slammed the door shut as he felt the young girl wrap her arms around him, looking up at him with a bashful look.

"No one saw you on the way here, right?" He asked the question he always opened up with every week.

"No one. No one at all." She answered.

Byleth was a man who took his role as a professor very seriously, spending countless hours teaching and aiding his students in refining their skills.

But even a man of his caliber had his limits and he greatly enjoyed the day off he had on a Sunday. A day spent fishing, reading or simply socializing with his co-workers and students offered enough variety to keep the day interesting while simultaneously allowing his batteries to recharge.

For the first few weeks of his time at Garreg Mach Monastery, this was the usual routine.

That is until one weekday. One of his talented students, Lysithea von Ordelia, requested some private study sessions; she claimed she wanted to improve her skills to an even greater level and wanted the professor’s help in doing so.

Byleth was hesitant at first as it would disrupt his free time, but she only asked for an hour each Sunday so he figured it wouldn’t do any harm. Besides, he was curious to see how much she could improve.

When the first study session arrived, she seemed strangely bashful. They couldn’t exactly use the classroom as it was meant to be free for all students during Sunday, so he instead asked her to meet him at his personal quarters.

His worries soon dissipated when they got properly into the study session and it resembled an ordinary seminar, albeit with just the two of them. 

These sessions would continue for a few weeks, but Byleth noticed Lysithea’s mannerisms change slightly every week. Occasionally, her speech would become stuttered, or her face would turn crimson-rose whenever he leaned in and explained something to her. 

Byleth was no fool to what this meant, but nothing progressed further from those awkward moments of embarrassment from the student. 

That is, until the young student, during a moment where their heads were dangerously close one week, pecked him on the cheek, forcing Byleth’s explanation of whatever he was talking about to come to a halt. He recalled gazing at her and immediately noticing the brightest blush he had ever seen soaking her face.

He questioned her with a somewhat stern tone, but when he received no reply, he simply rubbed her head and laughed it off, continuing on with his commentary on the study topic.

Lysithea didn’t respond too kindly to this, not satisfied with how he had handled the situation. Byleth suspected she was praying for him to return her affections, but he wasn’t going to be defeated that easily.

In a moment of frustration, she grabbed the far away side of his head, tilted it towards her and planted a kiss on his lips.

Byleth was momentarily shocked at the sudden confidence, but gave in to the warm embrace of her lips soon enough.

He knew all along his student had the biggest crush on him, and he certainly couldn’t deny he found her unbearably adorable at times, and that he admired her hard-working attitude.

He knew that answering his student’s feelings this way was riskful, but he couldn’t deny he had fantasized in private about her-- and a few other students too.

It was that day that Byleth and Lysithea began a forbidden relationship.

But Byleth knew exactly what would happen if somebody found out, so he made sure to establish some very important rules.

If Lysithea desired an intimate relationship with him, she would accept these conditions. 

And when he told her those rules, she didn’t mind one bit.

* * *

It had been several months since the two had begun their relationship. 

It had started off with simple kisses and light, curious touches. Despite Byleth’s preferences when it came to intimacy, he still cared about keeping his student comfortable. She was new to everything, after all.

Each week, they went further and further, with Lysithea adjusting well to every new step. As they progressed, he gradually introduced the conditions he had told her about.

It wasn't long before she accepted his desires.

She was now his. His to use. They had done so much together, and tonight was going to be no different.

Their session began no differently than usual, with Byleth eagerly prodding his tongue against the entrance to his student’s lips. Lysithea answered his lust promptly by opening her barrier immediately. He explored vigorously, the girl letting his tongue bash against hers, completely overwhelming it. With his hands gripping her cheeks, she let the older man use her mouth for his pleasure.

“Professor…” she cried out, breathing heavily as Byleth eventually broke the kiss. Only a slither of saliva connected them now. “I can’t handle this anymore… I need you.”

Byleth responded with actions rather than his words. His mouth lunged for her neck, planting a dozen kisses in a matter of seconds. While she tried to restrict herself at first, the younger girl couldn’t resist letting out quiet sounds of satisfaction that sounded incredibly sexy to her professor’s ears. The melody of her moans helped to urge her teacher, who intensified the pecks on the neck. But that melody came to an end as quickly as it came, Byleth breaking free from her neck and looking at her sternly.

“I told you not to call me professor, Lysithea. Not when we are in here, and alone.” He spoke to her with a slightly raised voice. 

“I’m sorry… Byleth.” Lysithea whispered in a hushed tone. It had taken the girl some time to adjust to the role of calling her professor by his name. It felt weird at first, but when she realized that she was the only one who called him by that name, she started to get used to it fast.

And as she got continuously used to the new name, he revealed a side of him that only she got to see as well. With her consent, he became more rough and dominant with her, and she was surprised to find out she didn’t mind the feeling of his strong hands groping her. 

During their privacy, she would still see the stern but gentle professor she fell in love with in the first place. However, she also saw a dominant and demanding man who knew what he wanted and wouldn’t take no for an answer.

It wasn’t long before she saw him in a new light. She saw him in a way no one else would. She treasured this secret.

And she loved how he treated her.

There were moments where he was kind and caring.

He would hold her closely as he whispered sweet nothings into her ear. Every affectionate word would make her heart skip a beat. Her favorite part was whenever he called her his favorite student, as it would always send her into a lovestruck meltdown that he found adorable. These were moments of complete bliss and tranquillity, and it felt oh-so-good to know she was so loved. 

Even when they made love, he would be tender and make sure she was feeling good too. Lysithea would never get tired of the feeling of his warm, protective hands resting on her belly after their intimacy. Just knowing that she was safe and protected would send her off into a peaceful, nightmare-free slumber. 

...There were also moments where he was cruel and merciless.

He would let his lust take over, lunging at her like a frenzied wolf. He would not hesitate to be rough with her body, grabbing and scratching away at her even though he knew his strength would hurt. But she didn’t mind, as she found the strange form of painful pleasure curiously addicting. He enjoyed pinning her down and locking her in place, ready to feast on his favorite prey. And when he did feast, she always melted at the overwhelming sensation of his rough, deep penetration. The sex was always messy and loud, and the wolf would continue to get hungrier as the night went on.

What stimulated her the most was the knowledge that whenever he was like this, she was his to use. She had no say. She couldn’t escape. She couldn’t even say no. She was his. Nothing more than a slave. And he would often call her that very word too. It was thrilling. Lysithea knew it was all ridiculously degrading… but that was what made it so arousing.

To this day, she couldn’t decide which side she preferred. The caring and tender Byleth was wonderful… but so was the Byleth that let his raw instincts take over.

It was bizarre. She loved being treasured and cared for. She also loved being completely dominated and used.

Perhaps the thing she loved the most was that it was him.

Today, she felt a little daring, wanting to bring out that tougher, more sinister side. She looked up at him with innocent eyes, juxtaposing his stern ones. “...will you accept my body as an apology? For calling you by the wrong name?”

Byleth knew her words were an attempt to get a rise out of him. He didn’t even care that it was working. Just looking down at her and seeing her narrowed eyes and crimson blush was enough to almost send him into a frenzy. Her messed up clothes weren’t doing any favors either, and neither was the droplet of sweat he saw sliding down her cheek.

He wasn’t going to let her win that easily, however. Kneeling down ever so slightly, he traced his fingers across her lips, scanning her expression as her breathing increased in weight. 

“I accept this apology.” He spoke calmly.

Lysithea’s mind felt like it was melting, not just because of his words, but also thanks to the large fingers stroking her smaller face, in position to grab her if necessary. She hoped he would. 

She did feel a little frustrated, however, as it was hard to read him currently. He still looked conscious with his decision making, but she also felt he was on the verge of snapping. He was indecisive on whether to treat her with care, or whether to teach her a lesson she wouldn’t soon forget.

Lysithea knew what she wanted though. Perhaps she needed to give him another push.

“...punish me.” 

Byleth’s fingers stopped. For a few seconds, he was frozen, enchanted by her soft, seductive voice. 

When he grew a slight grin, she knew she had won. 

“...have it your way.”

His hands hastily reached down and began tugging at her clothing, the force of which caught her off guard. It was an act he did when he decided to be rough and tough with her. Lysithea had grown to adore having her clothes grabbed and pulled, as it was a pleasant reminder that he was lusting over her- that he was losing his mind over her!

It satisfied her pride, knowing she was always able to drive him crazy.

But when her professor began unbuttoning her with the intention of revealing her chest, her confidence shrunk dramatically as she was snapped out of her thoughts. 

Lysithea quickly shielded herself, lightly guiding his starved hands away from revealing more of her body.

Byleth leaned back and saw she was struggling to maintain eye contact with him. He looked puzzled, but also frustrated at the sudden denial. 

“What’s the problem?” He spoke with an annoyed and harsh tone. She gulped, partly because of the sudden aggression, but mainly because she secretly adored how he sounded when he was frustrated at now being able to claim his prize. 

It made the unfortunate instinctive movement of her arms worth it, and the regret that came from it quickly passed. 

“There is no problem.” She spoke softly, raising her arms so they would no longer intrude on his feast. “I’m just teasing you.”

It had taken a long time for her body to grow used to the feeling of another person’s touch. It hadn’t grown fully accustomed to the sensation just yet, even if it was him, so she wasn’t surprised when her body reacted on its own as she was lost in her seductive thoughts.

But she trusted him. She knew she had nothing to fear from him.

Especially as he hadn’t judged her when he revealed her secret.

“I dare you to try teasing me again.”

Oh, now she was tempted.

Byleth lunged at her clothes once more, and more fiercely this time, easily displacing the buttons that were keeping her uniform kept together. 

The rugged skin around her small chest was one she used to desperately hide, even in front of her professor, but now, she found satisfaction in his mesmerising kisses she was now feeling on on her scarred skin. It was almost silly that her instincts tried to safeguard herself from him, but it was difficult to remove muscle memory that had been present her entire life. 

Byleth was the one person within Garreg Mach who knew Lysithea was covered in scars. When their intimacy began, this revelation was one she was certain would scare her professor away, but he was reassuring and even listened to her when she confessed to him her story.

She never would have guessed that he would end up swarming her body with kisses all over, making every fibre of her body shake and contract with unexpected pleasure. It was an… unpredictable response to her story, and she may have slapped him once or twice when he first did it, but she gave in to that exotic and strange feeling.

To this day, it was still strange to know that she was accepted despite her bodily defects. She used to hate her body- part of her still did, but knowing her professor loved it made her feel a little more confident in herself. 

He having scars aided this too, though his were from tough battles as a mercenary and weren’t as prominent as hers. It did help that he was willing to show his first, and that she was presumingly the first of his students to see them. It made those first days of intimacy more comfortable for her.

What she was most thankful for was that even though he could be rough and tough with her, he would never say cruel things about her body. 

During her thoughts, her master had easily discarded her bra and had started nibbling away at a nipple, the sensation of which awoke her from her daydreaming. She hummed delightfully as her body shivered.

“Byleth...” she murmured, barely managing to lock eyes with him as she groaned at his touch. “So good…”

Byleth paused his worship, tilting his head up so he could lock eyes with her. He looked even more frustrated, but was at least sane enough currently to answer her. “Meals don’t talk, Lysithea. Stay quiet and let me do the work.”

She had no reason to argue against that, as distracting him too much would snap him out of that trance she knew was building up inside him. He was close to letting his instincts take over and she couldn’t wait for it.

The professor continued to pleasure her chest with increasing vigor, but inevitably began making his way downwards, planting kisses all over her lower torso.

When the remaining attached clothing got in the way, Byleth wasted no time in tearing them off, leaving the young girl completely topless. 

Lysithea’s rosy cheeks grew in warmth. She wasn’t sure if it was because she was still bashful about being exposed before him, or because she knew that he was literally losing himself to lust with every passing second.

She noticed he was staring at her. Lysithea wondered what he was thinking, but she had a feeling he was beginning to truly realize that she was giving himself to him.

Byleth was lost. He couldn’t get enough of her body. Her warm blush. Her heavy breathing. Her beautiful scars. He couldn’t get enough about the gorgeous sight in front of him.

She was looking at him, undoubtedly eager to see what he would do next. She wanted him. She needed him! He needed her too. He couldn’t keep his mind focused at all. 

Byleth suddenly lunged towards her, forcing Lysithea into an overpowering, dominant kiss. The impact of his leap sunk her body into the bed as his weight overtook hers. He rested his hands by her shoulders, leaving her in a position she had no chance to escape from, and the realization of that made her feel even warmer inside. 

While his technique was sloppy, it was absolutely full of lust and greed. She could barely kiss back as he greedily forced his tongue into her mouth. 

This was what Lysithea had been waiting for.

He was a wolf. She was nothing but a meal.

The two inevitably and reluctantly broke the kiss when they had to both breathe. While she couldn’t see it, the area around her mouth was drenched in saliva, and the duo had to wipe away any lingering lines that connected them still.

Lysithea squealed internally at the entire situation, finding the professor pinned above her half-naked body incredibly enticing. She reached out her hands to the back of his neck, lightly pulling his body toward her own to give him some direction. He obliged, wasting no time in returning to covering her neck in an endless amount of kisses and endless bites, of which she always let out a long, satisfying moan. 

Then he bit.

Whenever he was like this, he would not hesitate with digging his teeth deep into her neck, biting hard enough to leave many noticeable marks. She didn’t resist despite the agonizing feeling of each bite, as while it did hurt, it felt intoxicatingly good as well. 

When Byleth eventually retreated, Lysithea breathed heavily in order to recover from the ordeal. However, the professor was not so willing to let her rest that easily. He made his way down her body once more, this time no longer restricted by her clothing. Just as she was beginning to feel a little less light headed, Lysithea let out a shriek at the sudden excruciating feeling coming from her chest.

Her eyes gawked down, watching her professor greedily sucked on one of her nipples, coating it in saliva. It felt as astonishing as before, but that feeling increased tenfold when her hardened nipple was suddenly pinched by his teeth. The result was an electrifying feeling that pulsed throughout her body, confusing her body on whether it was meant to be feeling pleasure or pain. 

It was a very unique kind of feeling that Lysithea wasn’t sure how to describe, other than it hurt so good. Her state of mind certainly wasn’t helped when her other nipple was catered to by one of his rough hands that twisted it in all sorts of directions. The whole act was making her moan, even though she was trying her best not to make any noise.

She felt dizzy. She felt like she was going to faint. It hurt. It hurt so much. But it felt good! It felt so good! 

She was only given time to breathe properly whenever Byleth stopped tormenting one nipple,but that moment was always short lived as he quickly began to feast on the other, restarting the process.

Lysithea lost track of how long this lasted, but when Byleth finally decided he had eaten this part of the meal, part of her wished he would just start over and never, ever stop.

“Byleeeettthhhh…” she groaned, vocalizing her thoughts in the form of lustful, barely comprehensible moans. “I… want… m-more…”

Byleth grinned at the state the young girl below him was in. 

Lysithea was boiling. She was sweaty. Her eyes were stained with the formation of tears, remnants of the pain she had felt. 

She was staring at him again. 

There was only one word Byleth could use to describe the emotion he was seeing in her sparkling eyes. Desire.

He desired her too, and he certainly wasn't done playing with her yet.

He returned to her body, showering her stomach with kiss after kiss.

Lysithea knew what he was going to do next. He was working himself lower and lower…

She felt her heart rate increase astronomically, both due to the warm feeling of the appetizer her professor was giving her, as well as anticipation for what was to come. That feeling only intensified when he tugged on her lower garments, quickly sliding them down her legs and off her body entirely, leaving her almost in the nude.

Byleth soon backed away slightly, moving his face to align a little bit away from her crotch, still safeguarded by the only piece of clothing left on her body. As if to give him a little extra encouragement, she opened up her legs a little more.

The professor prodded the fabric with a finger, letting it sink in a little. Lysithea faintly yelped as he toyed with her and heard her light hums.

“Byleth… please…” she begged, moving her hands to her underwear and slowly peeling them downwards, making sure her professor was watching carefully as she did so. She watched as his expression grew more feral as she exposed herself bit by bit to him. As soon as her privates were fully revealed, she hastily discarded her undergarments, kicking them off her body.

Byleth simply observed her most precious place, as if he was scanning every single detail. This left Lysithea a little frustrated. She was ready! He just needed to… do it.

“Please… I can’t handle this any-”

She yelped when Byleth unexpectedly gripped the middle of her thighs and pulled her forward, his face crashing directly into her crotch. Not wanting to give her time to recover, he stuck out his tongue and wasted no time in soaking up all of her leaked juices.

Lysithea felt her head fall back and her mouth prod open, the sudden pleasure leaving her breathless. Her legs instinctively closed, her thighs wrapping themselves around Byleth’s face and preventing him from escaping, though she had no doubts he could break himself free if he wanted to. 

Luckily for her, Byleth showed no signs of backing down, instead deciding to intensify the alternating of licks and kisses against her privates. The feeling of her cushy thighs against his face was a bonus that felt surprisingly good and gave him further encouragement to go down on her with as much energy as he could muster.

Lysithea’s mind was in a state of incomprehension. He had completely caught her off guard, his staring simply a ruse to surprise her. And now? She could feel nothing but pulsating pleasure that echoed through her entire body. He was greedily licking and sucking away at her pussy and it was driving her completely insane. 

And he was showing no signs of slowing down.

“Byleth…” she managed to let out an audible word, but he only heard the pure uncontrollable lust leaking out of his voice, a sound so wonderful that he rewarded her leaking pussy with intensified sucks and licks, making sure to cater them all around the vicinity of her clit. 

The feeling in his only groin was growing too uncomfortable to ignore any longer. While he stayed dedicated to his student’s genitalia, finding the vocal response to the worship of her clit especially pleasing, he managed to return his hands to his body. He soon freed himself from his belt, albeit after a few sloppy failed attempts as he was too focused on not letting those wonderful wails disappear.

The feeling of jerking himself while simultaneously eating this girl out was a wonderful combination and Byleth knew he was loving every moment of it.

Every ounce of pleasure he gave to himself, he made sure to also give to his talented little sorceress, either through a long-lasting lick that sunk a little into her insides or by sloppily kissing and sucking away on her clitoris. 

Lysithea responded wonderfully, soon placing her hands on the top of his head and gripping his hair, as if she was attempting to push him deeper in but couldn’t quite muster the energy to do so. 

“Byleth, I’m…!” 

As soon as he heard those words, he stopped, forcing his head out of the lock Lysithea was trying to keep it in. She offered little resistance, her shock at that wonderful feeling that was building up suddenly fading being enough to preoccupy her mind. 

"W-why…" She murmured, her eyes watering at the denial.

"You told me to punish you, Lysithea." He answered her immediately, noticing her mouth curve into a frown as she began to whimper. "So I did."

"Please…"

"Please what?"

"Let me… let me cum…" she groaned, her eyes continuing to water up at the state of her body. She was ridiculously horny and craved for release, but just as she was about to reach that exit, the door shut hard. She felt unbelievably frustrated.

"No."

She knew Byleth could be physically harsh with her, but not emotionally. It felt… bizarre, but just watching his smug grin was somehow making her feel even more horny, and she hated that she was feeling that way! She didn't even know why. Perhaps it was due to how aroused she currently was and how ridiculous her state was likely looking to him. She at least knew she needed to get off fast. She just needed to convince him somehow.

"Let me cum… and…"

"And?" He interrupted her, making sure she couldn’t backpedal. 

"...I'll let you do anything to me."

"Anything?"

"Anything! You can… do anything… punish me however you like after… just let me cum! Please! Please!"

He had never heard her sound so desperate before. But he was going to give her credit for something- this girl was very convincing when horny.

So when his tongue once again touched her clit, she began to squirm endlessly. When he began to suck and soak her in his saliva, her body spasmed at a faster rate as her begging turned into lustful sounds of joy.

Byleth responded to these sounds by simply speeding up himself, which accomplished what he hoped. Lysithea’s moans, already high in quantity, began to dramatically speed up not only in frequency but volume. The grip she had on him tightened and her body shook with adrenaline.

Byleth saw her legs move somewhat erratically as her orgasm overwhelmed her. He looked up at her arms, which refused to stay in one place. He then gazed up at her head, which was tilting from side to side, her mouth permanently open and letting out all sorts of wonderful noises.

Her hands shook and her toes curled inwards as every part of her body jolted with an intense amount of pleasure. Everything ached, yet it felt so good. Her body was drenched in hot sweat, but it felt so good. Her body was twisting awkwardly, but it felt so good.

These few seconds were nothing but heavenly to Byleth’s ears, who was still greedily cleaning up and drinking the juices of her pussy. 

Lysithea’s climax finally reached its conclusion and Byleth begrudgingly backed off, using this time to clear his face of the mess she had made with his coat sleeve. 

A moment passed, which was desperately needed for Lysithea to calm herself down and recover. Unfortunately, while she was given ample time to breathe a bit, it wasn't enough for her to fully recover before she suddenly felt hands on her hips, followed by her entire body being pulled off the bed. 

She fell into her professor’s arms, allowing her to stand on her own two feet. Inspecting Byleth, she quickly noticed the man had completely stripped, but what was mainly on her mind was how hard he was, something incredibly noticeable with their bodies squished together. She could feel his length tickling her belly and it was filling her with excitement. A slight smirk formed on her face, knowing the state her professor was in was all thanks to her.

When she felt his firm hand touch her crown and push downward, she knew what she had to do. Lysithea wasted no time in falling to her knees, positioning her face close to his cock. Just being so close and being able to smell him like this was almost sending her into a lust-driven frenzy of her own. It was becoming hard to concentrate, especially knowing that if she were to touch it or place it anywhere near her mouth, she may just lose control herself.

She raised her hand a little timidly, but the thought of her professor thinking she was acting like a child if she showed any signs of being scared were enough for her to stop her hesitation. With her lifted hand, she wrapped it around the base of his dick, feeling its hardiness against her tiny hand.

From Lysithea’s perspective, Byleth looked absolutely huge, his dick standing long and proud. She had only just recovered from her orgasm yet she could already feel her insides stir up once more just watching as it twitched ever so slightly. Her hand began to slide downwards with minimal speed, her eyes gazing up at his to see his reaction.

Unfortunately for her, Byleth took advantage of her distraction. While she was occupied with reading his expression, he prodded his shaft towards her lips, the surprise notion enough to force the girl’s mouth open a little, enough to envelop the head of his dick with her lips, forcing her mouth even further open. 

As soon as he felt their softness tickling his most sensitive part, he lost it. With a quick grab of her head, he pulled her body towards his own, sinking his entire cock into the depths of her mouth.

Lysithea gagged hard, making all sorts of incomprehensible noises. Her throat desperately attempted to force him out, but it wasn’t budging in the slightest. It felt unbearable, but just knowing what was now deep inside her and who it belonged to was enough to offset that feeling by quite a bit. 

“Does it hurt?” He asked, surprisingly sincerely, stroking her hair as if she was a pet. “Maybe you'll prefer this."

He began to pull out, and Lysithea was thankful she was being given a chance to breathe a little easier. She of course didn’t mind her throat being fucked like that, she was used to him doing it after all, but she wanted some time to prepare.

...her hopes faded when he suddenly slammed everything back into her throat. This time, her gag was worse and her eyes began to water significantly.

She couldn’t breathe.

He was too big. She wasn't ready.

He pulled some of his length out again and while she enjoyed the brief moment with her gag reflex fading, she wasn’t surprised at all this time when he forced it all the way back in.

Everything felt unbearable.

...but she would be lying if she said she didn’t love it.

Balancing her hands on his thighs, she let him thrust endlessly in and out of her mouth. Byleth continuously used her head to pull her towards him as he thrusted, doubling the speed his cock was entering and leaving her mouth. 

Over time, she got used to the sensation of her throat being constantly ravaged. Her mind wandered into nothingness as her professor used her for his own pleasure. She tried her best to pleasure him back, sucking him whenever possible and making sure her mouth was always covered in saliva. In fact, she was pretty sure she was doing it subconsciously by this point. Lysithea didn’t know how long this ordeal lasted for, nor could she even try to keep track of time. Her mind was empty.

When Byleth eventually pulled out for good, he noticed Lysithea was still in a half-conscious state. Drool was quick to fall down her mouth and her body shrugged downwards thanks to her hands leaving his legs. Byleth found her almost broken state to be incredibly alluring and he was half tempted to continue the conquest of her body, but he had his own limits and needed to rest. That didn’t mean their private time was over, however. All that was needed was a change of position.

The teacher sat down on the edge of the bed and beckoned his student over. Lysithea answered immediately, turning around to face his cock, eager to resume the blowjob even if she physically looked like a mess. 

Lysithea took a moment to regain her senses and returned her attention to Byleth’s dick, using her hand to grip near the top. She still felt a little uneasy, so for now, she just wanted to get a feel for it. With one hand focused near the tip, she moved it upwards and wrapped it around the head, feeling its squishier texture. With her other hand, she drifted it downwards towards his balls, making sure to be gentle with them when he instructed her to do so.

While none of the textures by themselves were extraordinary, knowing it was her professor’s cock that she was feeling up helped snap her back to reality. The slightly more rugged breathing coming from her professor was a welcome addition to cleansing her ringing ears too. It didn’t take too long for her to feel at ease again.

Lysithea hastily leaned forward and stuck out her tongue, licking the tip of his head. Byleth’s body shook and she felt it. Satisfied, she tilted his manhood upwards and stuck out her tongue again, trailing it downwards until she reached the base. She backed off momentarily, mesmerizing a little at what she was doing; sure, it wasn’t the first time she had done this kind of thing to her professor, but sometimes the reality of the situation got to her. 

The mage found herself staring at her professor erect cock for a few seconds, a little bit of drool leaking out of her mouth. She had only just recovered, but she couldn’t help but desire what she had just experienced.

“Lysithea, show me your skill. I want to see what you can do.”

The little student looked up at her professor with curious eyes, and was met with a demanding stare. She slowly nodded and pointed her head back down. Prodding the tip with her tongue once more, she circled the head for a bit to mentally prepare herself. Once ready, she closed her eyes, prodded her lips against the head and pushed. Soon, the tip broke through and her mouth opened, allowing the head-- and a little more after that, to sink into the warm wetness of her mouth. 

It didn’t take long for Lysithea to reach her limit, but she made sure to suck her cheeks in and bury as much of his length as she could with her slobber. The feeling of her professor’s member in her mouth and resting on her tongue was incredible, but she knew she had to do more if she wanted to make him cum. 

She tried to take him in deeper, but her gag reflex quickly intervened, the foreign feeling ejecting his cock with a loud pop; the only thing connecting them now being a messy string of saliva. This wasn’t enough to deter her, as she quickly gobbled him up again and worked on sucking him in and out. It took some work, but she soon found herself a rhythm that worked and made sure to keep his shaft drenched in her liquids.

Byleth placed his hand on her head, somewhat mimicking what she had done when he was pleasuring her. Lysithea only felt more encouraged after this, taking in a bit more of his cock. The gag reflex was still there, but she managed to resist it enough. By this point, she was able to take in about half of his length, but she wished she could consume it all.

“Not bad...” Byleth offered his verbal approval, albeit with a few pauses in between whenever his adorable student took his dick in as far as she could.

Lysithea responded by speeding up the blowjob, her sucking and licking becoming slobbier and the friction between her lips and his cock creating loud sloppy sounds.

Slowly, but surely, Lysithea was getting used to the incredible girth that was overwhelming her mouth. Every time she tried to fit more in, she was able to do so, even if it was only by a little. Every time the roof of her tiny mouth was poked by her professor’s large mass, she felt her only private place twitch in excitement as if it too was begging to get a taste. 

“But now it’s my turn.”

Byleth suddenly placed his hands on the top of her head and pushed her body towards his own, forcing his entire length into her mouth. The tip entered her throat and she felt herself gag almost uncontrollably, but she held on, finding the sudden forced fuck of her throat literally and figuratively breathtaking. Her eyes began to grow cloudy as she barely managed to control her breathing. It was just like when he had forced it all the way inside her before, but this time she felt like she couldn’t escape at all thanks to his hand stopping her from retreating.

Everytime he thrusted in and out of her at ludicrous speed, she felt her breathing get worse and worse.

...and once again, she was loving it. She felt so used. But… she loved it. Her professor had really shown her how much of a sexual degenerate she really was, hadn’t he? Or perhaps it was the other way around.

Before she could begin getting used to breathing through just her nose again, she felt a warm liquid paint the walls of the throat. It didn’t take long for her to figure out that her professor was dumping all of his cum inside the depths of her mouth. The thought of this and the sheer feeling made her eyes widen, and she didn’t even notice her fingers subconsciously trace down towards her newly drenched pussy. 

The professor released his cock a little, only to push it back in again, disposing of any remnants of his semen inside her. She swallowed unconditionally. As he used her mouth, she listened to his rugged moans of pleasure, sounds that sounded so sexy to her ears that it encouraged her to endure the uncomfortable yet strangely fascinating feeling she was experiencing. 

Soon, Byleth released his dick from his student’s mouth, endless strings of saliva connecting her lips to the tip of his member. Not only was her mouth a mess, but so was his cock, covered in her slobber from head to base. 

Lysithea looked at him with a smirk, which was an adorable sight paired with all the saliva and remnants of cum covering her face.

It was also the exact look he needed to turn him on again, and he didn’t want to let her get away with grinning at him like that without an appropriate punishment.

Lysithea was small in height, which also meant she was light in weight. She yelped as she was easily picked up and guided onto the bed by Byleth, who placed her onto her back. Even though she was free from his grasp, she still felt immobilized due to the two large hands now beside her head. Lysithea looked up and saw the lust-driven face of her professor staring down at her and it made her own cheeks grow rosy in response. She knew what he wanted to do next. 

Byleth aligned himself up with her entrance and pushed his entire manhood inside in an instant, not giving his student a chance to prepare herself. Lysithea immediately dug her fingers into the bed in response to the astonishing speed, but she soon moved her hands to her man’s back as soon as he properly climbed on top of her. Byleth took a moment to position his body comfortably before he began thrusting in and out of her, starting slowly but hastily speeding up.

She recalled their first time and how unbearably painful it was. He had taken her in her arms and apologised endlessly for hurting her, an act of kindness that had made her fall in love with him even more. But over time, she had grown used to it. There was still some pain to an extent, as her body wasn’t currently built for a man of his size, but it was nothing she couldn’t endure and the pleasure had amplified with time. By this point, she could handle him when he desired nothing more than to pound her ceaselessly.

And that is exactly what he was doing right now. All she could do is move her hands onto his back and hold onto him for support as every thrust emitted satisfying groans out of her body. Every knock on her cervix simultaneously hurt and felt so good, and there weren’t any signs of her professor stopping anytime soon. 

Lysithea couldn’t get enough of how much she was being craved right now. She wished she could see him continuously thrust into her, but having her sight being blocked by his large muscular body wasn’t a bad alternative. At the very least, she could see his face distort as he became overwhelmed with pleasure. 

As she pulled him in for a kiss, he quickly took control of the embrace. Lysithea wrapped her arms around his neck, stopping him from escaping, but he responded by digging his arms underneath her body so he could grasp her back. Upon doing so, Byleth lifted himself up and took Lysithea with him, who instinctively wrapped her legs around his waist as he held onto her.

Byleth was now standing with a girl half his size riding his cock, and knowing he had complete control only sped up his thrusts, his cock constantly bashing against the entrance to her womb. Lysithea melted into the kiss as she was easily fucked thanks to her professor’s strong body and her light weight. When she had to retreat to breathe, her head collapsed onto his shoulder. She felt so lightheaded she almost thought she was falling, prompting her to dig her nails into his back, which only made Byleth even more vigorous.

He was too fast. It hurt. She was feeling dizzy. Was he going too far? Part of her said yes. Part of her said no.

“S-stop…” her body cried out for release from the overwhelming sensations, making the decision for her. “It hurts…”

Byleth tilted her head upwards and quickly bit into her neck, showing his response through actions. Upon releasing, he used a hand to playfully stroke her face.

“I know it hurts, Lysithea.” He told her. “But this is your punishment. You told me I could do anything I wanted, didn’t you?” 

“Cruel…” She murmured.

Byleth pushed, filling up her entirely before pausing. She moaned in response at being completely filled up. He scanned her face and saw some potential truth to her words, as her eyes were beginning to tear up quite a bit.

But he wasn’t convinced.

He stroked her face again, almost in a condescending-like manner.

“You like the pain, Lysithea. You like it when I hurt you.” Byleth began, taking a moment to suddenly pull his cock out. She whimpered at the feeling and immediately began to miss its warmth.

“P-Put it back in…” she tried to redirect the conversation.

“It hurts you when I put it in though, right? Is that you admitting that you like the pain?” He quickly questioned her.

A bashful blush formed on her face as she bit into her lip. “N-no…”

“Admit it, or I’m not putting it back in.” He warned her.

Byleth could not get enough of how Lysithea was acting right now. She was in shambles, trying her best to think of something to say that wouldn’t directly admit the truth. He could tell she was growing very frustrated though with the absence of his dick deep inside her. She was squirming and letting out needy huffs and it was simply adorable.

“Fine… I like the pain!” Lysithea finally admitted. “Are you happy now? Now put it back in already!”

“Why do you like the pain?”

“I… I don’t know how to answer that…” she returned to being a little shy again.

“I want you to tell me..”

She was so tempted to childishly bash on his shoulders out of frustration, but she didn’t, for obvious reasons. Instead, she opted to avoid eye contact for a while as she thought up an answer to tell him. 

“I… just like it…” she stated a basic answer, but upon seeing Byleth’s unamused expression, she groaned annoyingly but then sighed. “...and I like that it's you who is doing it.”

Byleth lightly laughed at her response, which didn’t help with how annoyed Lysithea was with him. He silenced her frustrations with reaching a hand to the top of her head, patting it while a smile grew on his face.

“H-hey!” she called out to him. “This is not the time to treat me like a child, so I suggest you stop doing-”

Lysithea screeched. Byleth was thankful it was so easy to distract her, as it meant him abruptly entering her even more surprising for the girl. Lysithea quickly intensified the grip she had on her professor as a wave of pleasure overpowered her body, ending in her collapsing onto her body as he supported her weight entirely with her own hands. Her loss of control over her body was so great that she felt like she was going to fall, but she completely trusted that her professor wouldn’t let that happen. Knowing she was safe, she gave in to the odd agonizing bliss, letting Byleth have his way with her.

Both Byleth and Lysithea lost themselves to the simultaneous pleasure. Byleth continuously thrusted all the way inside her, pushing deep against her cervix. Whenever he needed to pause to take a quick break, Lysithea took to riding him herself. While she wasn’t as fast, it was enough to keep their bodies satisfied and turned on.

Eventually, Byleth found his own legs giving away and forced Lysithea back onto the bed, resuming the position they were in earlier. He kept his dick firmly inside her, meaning it took no time to continue having sex. The sudden movement was enough to bring Lysithea close to her climax, and her professor felt it too as her walls began to squeeze him relentlessly.

Byleth felt his own orgasm approach as well, speeding up to help quicken their ends. He couldn’t decide if he was enjoying her constant moans or how sloppy their sex sounded more, but nevertheless both were doing wonders to this lustful state of mind. 

With one final thrust, he collapsed on top of her, burying her face in his chest as they both groaned each other’s names. Their bodies ached tremendously from the constant pulsations but neither cared due to it feeling so, so good.

Lysithea could feel her entire pussy heat up tremendously as her professor dumped wave after wave of cum deep inside her, not only filling up her soaked hole but her womb as well. She moaned as Byleth wrapped his arms around her and pulled her in for a crushing hug, their orgasms reaching their finale.

As their moments came to an end, they remained in the same position, holding onto each other’s sweaty bodies.

Neither Byleth or Lysithea knew how long they spent in each other’s arms, but when they eventually came to their senses, they passionately kissed one last time and giggled a little at what they had just done.

“That was incredible… you were incredible…” Lysithea complimented her man.

“You were too.” Byleth offered his compliments back. “How are you feeling? Not too hurt, I hope?”

“No, I’m alright. A little sore, but I feel wonderful.” She responded, stroking his hair as she spoke to him. “I love when you’re on top of me like this. I feel so warm and safe...” 

“I still can’t believe how manipulative you can be in bed.” He chuckled, enjoying the warmth of not only her body but still being deep inside her. He could have continued fucking her, but he was far too exhausted. He didn’t care though, since he enjoyed how they were cuddling right now.

“I don’t see you complaining. You wanted to be rough with me from the start. Luckily for you, I love it when you’re rough. Perhaps I love it more.”

“Maybe. Maybe not.”

Lysithea yawned into his chest and fidgeted a little, humming into his chest after. “Is it okay if I stay the night?”

“Of course, but you’ll have to leave early in the morning as usual.”

“Okay.” She accepted his condition, yawning again. “I love you... professor.”

Byleth intensified the grip he had on her, enjoying her words greatly. “I love you too, Lysithea, but please, call me Byleth when we’re in here.”

“Sorry, old habits die hard.”

* * *

As promised, Lysithea got up early in the morning, ready to leave as the sun began to rise. Byleth got up with her, as he needed time to prepare the day’s teaching. 

The duo exited the professor’s room, with Byleth intending to see Lysithea off. 

What they did not expect was to see the tall figure of Dedue standing outside his door, staring directly at them. Him being there wasn’t too odd, since he lived next door to Byleth, but at this time in the morning was a first. Lysithea quickly retreated behind her professor’s body, though it was still fairly easy for Dedue to see her.

They merely stared at him for a while, unsure of what to say.

“Um… good morning, Dedue.” Byleth eventually greeted him, trying to think of an excuse for Lysithea’s presence.

The Blue Lion smiled in response. “Good morning, professor. As thanks for saving his majesty’s life, I will keep this forbidden relationship you have with your student a secret. All I ask in return is that…”

He paused, biting his lip for a few seconds. This was the first time Byleth had seen Dedue look hesitant to say anything, but he eventually gave in.

“I ask Miss Lysithea that she keeps it down when you two spend your time together. I would like my Sunday nights to be preferably peaceful. Thank you.”

“...uh, sure. Yeah, no problem.”

**Author's Note:**

> Lysithea is super cute. How could I not lewd her? I'll probably get around to a timeskip story with her at some point, but that's for another day.
> 
> Like my work? If you're interested in writing updates or want to support me, visit and follow my Twitter! twitter.com/KwIlsa33


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